Voltage and frequency responsive regulating circuit for a pm generator

ABSTRACT

A solid state regulating circuit for a permanent magnet alternator which includes a switching element, preferably an SCR, for shunting the output winding of the alternator in response to a control signal to limit variations in power delivered to a load, and a control circuit for proving the control signal in accordance with the frequency and amplitude of the alternator output. More particularly, the control circuit may include a diode connected to the output windings of the alternator to provide a half wave signal, a first capacitor for integrating the half wave signal to provide a monotonic intermediate signal of predetermined duration, and a second capacitor connecting the first capacitor and the gate of the SCR for providing the control signal for gating the SCR.

United States Patent 1 1 3,745,2 July 10, 1973 VOLTAGE AND FREQUENCY RESPONSIVE REGULATING CIRCUIT FOR A PM GENERATOR [75] inventor: George E. Gynn, Fort Wayne, Ind.

Assignee: Syncro Corporation, Oxford, Mich. Filed: Apr. 17, 1972 Appl. No.: 244,778

Primary Examiner-J. D. Miller Assistant Examiner-ll. Huberfeld Attorney-J. King Harness, William L. Anthony, Jr. et al. a l

[57] ABSTRACT A solid state regulating circuit for a permanent magnet alternator which includes a switching element, preferably an SCR, for shunting the output winding of the alternator in response to a control signal to limit variations in power delivered to a load, and a control circuit for proving the control signal in accordance with the frequency and amplitude of the alternator output. More particularly, the control circuit may include a diode connected to the output windings of the alternator to provide a half wave signal, a first capacitor for integrating the half wave signal to provide a monotonic [56] References cued intermediate signal of predetermined duration, and a UNITED STATES PATENTS second capacitor connecting the first capacitor and the 3,260,917 7/1966 Shimwell et a1. 320/61 X gate of the SCR for providing the control signal for gat- 3,242,346 3/1966 Skoubo 322132 x ing the SCR 3,619,763 11/1971 Wyles 322/32 55 Claims, 11 Drawing Figures A? /4 if a -l' 774 i?) j 1/ 6 L K Zi "'1" 4 PAIENIE JUL 1 0191s SHEET i [If 4 VOLTAGE AND FREQUENCY RESPONSIVE REGULATING CIRCUIT FOR A PM GENERATOR BACKGROUND AND SUMMARY OF THE INVENTION Many recreational and utility vehicles in present use are provided with relatively low-cost permanent magnet altemators to supply electric power for the vehicle ignition, battery and for various electrical accessories such as the vehicle lights. Since permanent magnet alternators do not utilize field windings, and consequently, the field strength cannot be directly controlled in the usual manner by controlling the excitation of the field winding, the regulation of the output of the permanent magnet alternator is ordinarily accomplished by a shunting circuit. for example, as disclosed in the patent to Carmichael, et al., US. Pat. No. 3,270,268. More particularly, regulation of the alternator is accomplished by switching a relatively low impedance path across the output windings of the permanent magnet alternator. In the above Carmichael, et al. system, the voltage of the battery is sensed by a zener diode and the output of the permanent magnet alternator is controlled thereby to maintain the battery voltage at a predetermined level.

In some systems, batteries are not utilized and consequently, a readily utilizable voltage standard for regulating the alternator output is not available. Nonetheless, it may still be desirable to regulate the output of the alternator. For example, consider a vehicle having a permanent magnet alternator for providing electrical energy to the lighting lamps of the vehicle. It will be appreciated that it is desirable from a safety standpoint to limit the power to the lamp to prevent premature lamp burn-out. It is also desirable, in addition to the above safety consideration, to regulate the generator output to control the intensity of the light emitted by the lamp.

The present invention providesa solid state circuit of relatively few components for regulating the power output of an electrical power generator such as a permanent magnet alternator. The regulating circuit preferably includes a solid state switch such as an SCR which is connected across the output windings of the permanent magnet alternator in parallel with the load, and a control circuit connected to the gate of the SCR for varying thefiring angle of the SCR so that the SCR represents a varying impedance in parallel with the load. The control circuit is connected to one terminal of the output windings of the permanent magnet alternator through a diode so as to receive positive half cycles of the alternator output waveform. The positive half cycles are delivered through a voltage-limiting resistor to a first capacitor which is connected to the other terminal of the generator output winding so as to integrate each positive half cycle, i.e., to provide an intermediate signal having a potential peak which lags the potential peak of the half cycle waveform at the cathode of the diode. For example, the circuit values may be selected so as to provide an intermediate signal at low alternator speeds having a potential peak which is shifted with respect to the potential peak of the half cycle waveform from 90 to slightly more than 160 of the alternator output cycle to provide a monotonic waveform for slightly more than 160 of the alternator cycle during which the SCR may be fired. Consequently, gradual regulation can be accomplished since the regulating circuit is capable of controlling the out- 2. put power by shunting the output winding of the alternator for only a small portion of each alternator output cycle, i.e., for less than 20 thereof, rather than making large reductions on spaced cycles. Consequently, large power fluctuations which cause lamp flicker are avoided. I

Insofar as the SCR is fired upon the attainment of a particular amplitude at its gate, and the amplitude of the gating signal is a function of the amplitude of the output of the alternator, the firing of the SCR is advanced in accordance with increases in the amplitude of the alternator output waveform, regardless of changes in the speed of the alternator. In this regard, the efficiency of an alternator increases with decreasing alternator temperature such that the amplitude of the alternator output increases with decreasing temperature although no change in alternator speed occurs.

The preferred regulating circuit also includes a parallel circuit of a resistor and a second capacitor which is connected between the first capacitor and the gate of the SCR. As the alternator output frequency increases, the rate of increase of the intermediate signal with respect to the alternator cycle decreases, tending to delay the firing of the SCR while an advance in the firing of the SCR is called for since the alternator output power is increasing. The parallel circuit of the second capacitor and the resistor ofi'sets this tendency by establishing a combined path to the gate for the intermediate signal which has a decreasing impedance as the frequency of the alternator output increases. This decreasing impedance with frequency increases the amplitude of the gating waveform so that the SCR is gated at increasingly earlier times with increasing frequency.

Also, as the alternator speed increases, the intermediate signal will experience a boost in DC offset, determined in accordance with the RC time constant of the circuit having the first capacitor, since the first capacitor will not have sufficient time to discharge. The latter effect is additive to the effect of the decrease in the impedance of the path from the first capacitor to the gate of the SCR toadvance the firing of the SCR with increasing frequency.

In view of the above, it will be appreciated that changes in alternator output power, whether or not the result of changes in alternator speed, are accommodated. The regulator of the present invention responds to such changes so as to limit the variations in power delivered by the alternator to a load.

It can be seen from the above that a circuit of relatively few components is provided by this invention which effectively accomplishes power regulation of a permanent magnet alternator. It will be appreciated that the circuit is manufacturable at low cost using solid state components to provide a durable and reliable regulating circuit which is especially suitable for use in the harsh environment of a recreational vehicle.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a circuit diagram of an exemplary regulating circuit according to the present invention;

FIG. 2 is a graph illustrating a typical output waveform of a permanent magnet alternator;

FIG. 3 is a graph illustrating the change in the resistance of a tungsten filament lamp as a function of excitation;

FIG. 4 is a graph illustrating the power dissipated in a permanent magnet alternator as a function of alternator speed;

FIG. 5 is a graph illustrating the power dissipated in a resistive load as a function of alternator speed;

FIG. 6 is a graph illustrating alternator efficiency as a function of alternator speed;

FIG. 7A is a graph illustrating a generalized control signal in comparison with a generalized altemaor output signal for a first alternator speed;

FIG. 7B is a graph illustrating a generalized control signal in comparison with a generalized alternator output signal for a second higher alternator speed; and

FIG. 8 is a graph illustrating the equivalent impedance of an intermittently shunting SCR as a function of the angle of conduction of the SCR with respect to the alternator output cycle;

FIGS. 9 and 10 are illustrations of additional embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, a regulating circuit 10 is illustrated which is connected across the windings 12 of a permanent magnet alternator at terminals 14 and 16. The alternator may be along the lines of that disclosed in the aforementioned patent to Carmichael, et al. A load R which may be the tungsten filament of an illumination lamp, is connected in parallel with the regulating circuit l0 and the output windings 12. The regulating circuit 10 includes an SCR '18 and a control circuit 20, each of which is connected directly between terminals 14 and 16. The SCR 18 provides a shunt path for the permanent magnet generator windings 12 when the SCR 18 is conductive.

The control circuit 20 includes a diode 22 which is connected to one terminal 14 to provide the positive half cycles of the alternator output waveform at its cathode which are received by a voltage divider network comprising resistors R1 and R2 so as to provide positive half cycles of reduced potential at terminal24. A first waveform modifying network comprising resistor R3 and Capacitor C1 provides an intermediate waveform at a terminal 26 having a configuration and purpose to be described in detail herinafter. A second waveform modifying network comprising a resistor 4 and capacitor C2 connects the terminal 26 to the gate of the SCR 18 to provide a gating signal for the SCR 18 which will also be described in greater detail hereinafter. An adjustable resistor R5 establishes an approriate control circuit output impedance which matches the gate input impedance of the particular SCR used. The resistor R5 is also used to fine tune the regulating circuit 10 after assembly, as will also be more fully described hereinafter.

To aid in an understanding of the operation of the regulating circuit 10 of FIG. 1, the various alternator and load operating conditions, which influence the operation of the regulating circuit, will be initially set forth.

In FIG. 2, a typical output waveform of a low cost permanent magnet alternator is illustrated. As can be seen in FIG. 2, the output waveform is distinctly nonsinusoidal and has significant energy in the odd harmonics. It can be seen that the initial positive monotonic portion of the curve occurs for less than the first 90 of the operating cycle of the alternator. In fact, the

output waveform of a typical permanent magnet alternator is even more complex than suggested by the chart in FIG. 2 since the configuration of the waveform varies with the alternator speed, i.e., frequency. Also, the output waveform generally increases in amplitude as alternator speed increases.

The operation of a regulating circuit for a permanent magnet alternator may also be dependent upon changes in the load impedance. For example, as illustrated in FIG. 3, the tungsten filament lamp has a positive temperature coefficient of resistance with excitation voltage so that the resistance of the lamp filament will increase as the voltage applied to the lamp filament increases.

With reference now to FIG. 4, the next factor to consider is the power dissipated in the alternator. Since permanent magnet alternators are subject to frequency-dependent losses in the iron and magnet structure, the air gap, the windings, and are further subject to losses due to stray reactances, the output power of the alternator does not vary linearly with alternator speed. Typical variations in the power losses of permanent magnet alternators as a function of speed are shown in FIG. 4. As can be seen in the figure, the losses within the alternator increase relatively rapidly with alternator speed, especially for low load impedances. Consequently, as seen in FIG. 5, the power provided to the load decreases with alternator speed. Therefore, as seen in FIG. 6, the efficiency of the alternator, defined as the percent power dissipated in the load with respect to the total power dissipated in the load and the alternator, decreases with increases in alternator speed.

In summary of the above, the configuration or shape of the alternator output waveform, the amplitude of the alternator output waveform, the load impedance, and the internal alternator impedance, vary with alternator speed. Each of these variations affect the power delivered to the load. Consequently, if power delivered to the load is to be closely regulated, each of the above variations must be accommodated by the alternator regulating circuit. The operation of the regulating circuit 10 of FIG. 1 will be considered in the light of the graphs of FIGS. 7A and 7B which are illustrative of generalized operational waveforms. It is cautioned that the waveforms of FIGS. 7A and 7B are not fully. representative of true waveforms, but rather, have been simplified to facilitate an understanding of the present invention. As one example, it will be readily aparent that the sinusoidal waveform shown in each of the figures, incorporated to represent the alternator output waveform, would more closely resemble the waveform shown in FIG. 2.

As previously stated, the potential at the cathode of the diode 22 represents the positive half cycles of the output waveform. This potential is reduced by the voltage divider network comprising resistors RI and R2 to some value less than full value, for example, approximately percent of the full value. The first signal modifying circuit comprising the resistor R3 and the capacitor C1 integrates the reduced positive half cycle waves so that the peak of the intermediate signal at terminal 26 lags the peak of the half cycle waves at the cathode of the diode 22. The wave at terminal 26 is represented in FIG. 7A as the lower waveform which is monotonic and increasing for approximately 162 of the alternator cycle. Consequently, the initial positive monotonic portion of the intermediate signal at terminal 26 is extended substantially over that of the signal at the cathode of the gate 22.

Considering for illustrative purposes that a network without reactive impedance connects the terminal 26 to the gate of the SCR 18 so that the lower signal of FIG. 7A is provided to the gate of the SCR 18, it can be seen that a monotonic signal, i.e., one which is suitable for gating the SCR I8, is available for a sufficient portion of the alternator output cycle so that the output can be regulated by shunting the output through the SCR 18 for as little as approximately 20 of the altemator output cycle. If it were not for the lag in the occurrence of the peak of the intermediate signal at terminal 26, it would be necessary to shunt the alternator output for a minimum of 90 of the alternator cycle so that the minimum power regulation which could be effected would be at a reduction in the power output of the alternator consequent the shunting of at least 90 of the alternator cycle. Accordingly, a more gradual decrease in the power output of the alternator can be accomplished with the circuit of the present invention.

Still considering the terminal 26 as being connected to the gate of the SCR 18 through a network without reactive impedance, it will be appreciated that as the amplitude of the output waveform of the alternator increases, the amplitude of the signal at terminal 26 will increase so as to reach the gating level of the SCR at an earlier point in time, and consequently, so as to advance the firing of the SCR to correspondingly reduce the power delivered to the load. Therefore, power regulation is accomplished as a function of the amplitude of the alternator output. The response of the regulating circuit to the amplitude of the alternator output waveform can be conveniently adjusted by adjusting the values of the voltage divider resistors R1 and R2 to establish the desired relationship between alternator output potential and the gating potential of the SCR 18.

With increasing frequency, the lag of the peak of the signal at terminal 26 with respect to the half cycles at the cathode of the diode 22 increases'somewhat. Also, the attenuation of the signal increases since the impedance of the signal path through the capacitor C1 decreases. However, although the attenuation of the signal is increased, the actual diminution of the amplitude of the signal at the terminal 26 is offset by the increasing amplitude of the alternator output waveform. Additionally, the RC time constant of the circuit having the capacitor C1 may be sufficiently long such that as the frequency increases, the capacitor C1 will not fully discharge before the next charge cycle is initiated. Consequently, a DC offset will occur which increases with increasing frequency to actually increase the intermediate signal at terminal 26 with increasing frequency. However, the DC offset does not provide an advance in the firing angle of the SCR 18 which is sufficient to offset the increasing power output of the alternator with alternator speed.

The second signal modifying circuit comprising the capacitor C2 and resistor R4 is used to advance the peak of the waveform at the gate of the SCR 18 with increasing frequency to fire the SCR 18 at increasingly earlier times to accommodate increases in the power output of the alternator with alternator speed. More specifically, the parallel connection of the capacitor C2 with the resistor R4 increasingly reduces the impedance of the path from the terminal 26 to the gate of the SCR 18 with increasing frequency whereby the signal level at the gate is increased. As can be seen in FIG. 7B, the firing point advanced to approximately of the operating cycle of the alternator and will continue to advance with increasing alternator frequency to nearly 45 of the alternator output cycle.

When the gate fires at the peak shown in FIGS. 7A and 7B, the potential supplied to the regulating circuit is reduced by the shunting of the alternator output windings so that substantially no further increase in gate signal occurs. If it were not for the firing of the gate at that point, a slight increase in signal may have occured before the charging of the capacitor C1 ceases, i.e., when the potential supplied to the capacitor C1 is no longer greater than the potential stored at the capacitor C 1.

When the SCR I8 fires, the output of the alternator is reduced substantially to zero so that the capacitor C1 begins to discharge through resistors R2 and R5. The discharge is at a rate established by the values of the capacior Cl and the resistors R2 through R5 so as to establish the downward slope in the gate signal curve of FIG. 7A and 7B. The capacitor will continue to discharge until it again is supplied with a potential from the alternator 12 which is greater than its instantaneous charge.

As will be apparent from the previous discussion, the values of capacitor C1 and the resistor R3 are selected in combination with the other circuit components to provide a time constant which, at the lower oprating frequencies of the alternator cause the peak of the intermediate signal at the terminal 26 to occur at nearly of the alternator operating cycle, for example, at approximately 162 of the alternator cycle. The values of the capacitor C2 and the resistor R4 are selected to provide an advance in the firing of the SCR 18 with increasing frequency in accordance with the operating parameters of the particular alternator and the characteristics of the load so that the power delivered to the load remains relatively constant. The resistor R5, as previously stated, is generally selected to provide an appropriate control circuit impedance at the gate of the SCR 18. Additionally, the resistor R5 is adjustable so as to finely tune the regulating circuit after assembly so that a high degree of accuracy in regulation is obtained. Since the gate of the SCR 18 has a relatively low impedance, preferably, the resistors R1 through R5 have relatively low values of resistance.

As will be appreciated in view of the above description, the regulating circuit 20 varies the angle at which the SCR l8 fires with respect to the alternator cycle. This variation in conduction angle appears to the alternator like a varying load which is in parallel with the normal load. More specifically, as the generator output increases, the varying load increases, i.e., its impedance decreases, thus holding the power available to the normal load relatively constant. As can be best seen in FIG. 8, the SCR l8 equivalent impedance falls off rapidly as the conduction angle at firing increases to approximately 90 and falls off less rapidly thereafter. Referring now to FIG. 5, it can be seen that the power dissipated in the load when the alternator is unregulated rises rapidly initially and less rapidly as alternator speed increases. Consequently, it can be seen how the control circuit 20 can be adjusted such that the SCR equivalent impedance decreases rapidly initially in accordance with the rapid initial power increase at the alternator, and less rapidly with the less rapid power increase at the alternator as the alternator speed increases so as to be matched to the alternator power characteristics so that the load receives substantially constant power.

In an exemplary operating embodiment of the present invention, the following circuit values and components were used:

Name No. or value Generator 122 Watt, 12 Volt, 12 pole, mfg. by Syncro Corp.

boad two General Electric 4445 bulbs at 35 watts each bulb and two General Electric 1157 at 26.9 watts each bulb Diode 22 IN 4004 SCR 18 General Electric C 122 Bx 23 In the above exemplary embodiment, the resistors R3, R4 and R5 were provided by depositing a resistive, thick film ink on a ceramic substrate. The resistive film of the resistors R4 and RS have selected temperature coefficients of resistance so as to compensate for variations in the firing sensitivity of the SCR 18 with temperature so that the SCR 18 will fire at a given potential at terminal 26 substantially rgardless of variations in the operational conditions of the SCR 18 which affect its temperature. In this regard, the resistive film of the resistor R5 has a negative temperature coefiicient of resistance while the resistive film of the resistor R4 has a positive temperature coefiicient of resistance. Since the resistor R4 is essentially in series with the gate of the SCR 18 and the resistor R5 is essentially in shunt with the gate of the resistor of the SCR 18, the effects of the temperature coefficients of resistance of the resistors are additive, i.e., effect of each on the firing sensitivity of the SCR 18 is in the same sense. If the temperature sensitivity of the SCR 18 is sufficiently small, either the resistor R4 or the resistor R5 may have a zero temperature coefficient of resistance.

In the calibration of the regulator the resistor R5 is first trimmed so as to provide a predetermined firing sensitivity of the SCR 18 in volts and milliamperes at the junction of the resistors R4 and R5. Thereafter, the resistor R4 is trimmed so as to provide a predetermined firing sensitivity of the SCR 18 at the terminal 26.

In FIG. 9, a full wave regulator is illustrated in combination with a resistive load R which may be a lighting lamp and a battery 32 which is connected to the output winding 12 of the alternator by a full wave rectifying bridge consisting of diodes 30-36. The full wave regulator essentially comprises a pair of half wave regulators l0 and 10' which are connected in parallel and in opposite polarity relationship. Each of the regulators 10 and 10 are essentially as described with respect to the regulator 10 of FIG. 1 except that the values of the components are adjusted so that the shunting of each half cycle occurs at a time later than the time of shunting of a half wave regulator in accordance with the increased regulating effect provided by full wave regulation. As can be seen in the figure, the regulator 10 is connected to the winding 12 to shunt on one half cycle of the alternator output while the regulator 10 is connected to thewinding 12 to shunt on the other half cycle of the alternator output.

In FIG. 10, a voltage regulator 40 according to this invention is illustrated in combination with a battery 42, a rectifying diode 44, and lighting or lamp load R The regulator 40 is like the regulator 10 of FIG. 1 except that it additionally includes a Zener diode Z1 to provide high voltage transient protection. For example, high voltage transients may occur upon opening of a starter motor switch or other load switch. As can be seen in the figure, the Zener diode Z1 is connected between the cathode of the diode D1 and the gate of the SCR 18 so that a voltage exceeding the Zener diode voltage, for example 200 volts, at the cathode of the diode D1 will cause substantially instantaneous firing of the SCR 18 so as to absorb the transient in the SCR 18. A Zener diode is selected which has a breakdown voltage which is lower than the peak voltage rating of all other devices subject to excess transient voltage damage. Consequently, solid state devices or other devices connected to otherwise receive the voltage transient are protected. It will be appreciated that a pair of the voltage regulators 40 having the high voltage transient protecting diode Z may be used in a full wave regulating circuit as shown in FIG. 9 so that both positive and negative high voltage transients are accommodated.

Although the regulating circuit of the present invention has been described in combination with a permanent magnet alternator, those skilled in the art will appreciate that the teachings herein may be applied to other types of electrical power generators, and especially those providing an output waveform having a cyclically variable amplitude. For example, the regulator of this system may be used to regulate the fluctuating DC from a rectifying circuit which is connected to the output windings of a permanent magnet alternator. By way of illustration, the regulating circuit 10 may be connected to the output of a full wave'bridge rectifying circuit which is connected to opposite ends of an alternator output winding, or may be connected to the cathodes of a pair of diodes connected to the opposite ends of the output winding of a permanent magnet alternator having a grounded center tap.

Considering the complexity of the parameters influencing the power delivered to the load which change with alternator speed, and considering the changes in alternator output which occur even without changes in alternator speed, it will be well aprreciated that the above circuit uses unexpectedly few components. Moreover, it can be seen that the control circuit is fully solid state, and consequently, can be built for the rugged environmnet of snowmobiles and other recreational vehicles simply by encapsulating the components. It will also be appreciated that due to the wide range of regulation provided by the regulating circuit 10 of this invention, large power fluctuations are avoided such that power ripple, aswould cause lighting flicker, are minimized.

It will be appreciated by those skilled in the art that the preferred embodiment of the invention disclosed herein is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

I claim:

1. For a permanent magnet generator having an output winding for providing an alternating current output having a waveform of varying amplitude and being adapted for connection to a load for providing at least a portion of said output to said load, a regulator adapted for connection to said output winding comprising switch means being operable for establishing a relatively low impedance path across said output winding responsive to a control signal, and control means receiving at least a portion of said alternating current output and responsive to the frequency of said output for providing said control signal to cause selective operation of said switch means to limit variations in the power level of said portion of said output received by said load.

2. The regulator of claim 1 wherein said control means includes a device having a reactive impedance receiving at least a portion of said output portion received by said control means for modifying said output portion received thereby in accordance with the frequency thereof.

3. The regulator of claim 2 wherein said device having a reactive impedance is a capacitor.

4. The regulator of claim 3 wherein said capacitor integrates said output portion received thereby to provide monotonic signal of predetermined duration which is greater than the monotonic duration of the corresponding waveform of said output.

5. The regulator of claim 2 wherein said capacitor is connected so as to have a decreasing impedance with increasing frequency so as to increase said control signal in accordance with increases in the frequency of said output portion received thereby.

6. The regulator of claim 5 further including a resistor connected in parallel with said capacitor.

7. The regulator of claim 4 furhter including a second capacitor connected so as to have a decreasing impedance with increasing frequency so as to increase said control signal in accordance with increases in the frequency of said output portion received thereby.

8. The regulator of claim 7 wherein said second capacitor receives said monotonic signal from said first capacitor.

9. For a permanent magnet generator having an output winding for providing an alternating current output having a waveform of varying amplitude and being adapted for connection to a load for providing at least a portion of said output to said load, a regulator adapted for connection to said output winding, said regulating means comprising switch means being operable for establishing a relatively low impedance path across said output winding responsive to a control signal, and control means receiving at least a portion of said alternating current output and responsive to the frequency and amplitude of said output for providing said control signal to cause selective operation of said switch means to limit variations in the power level of said portion of said output received by said load.

10. The regulator of claim 9 whzrein said control means includes a device having a reactive impedance receiving at least a portion of said output received by said control means for modifying said output portion received thereby in accordance with the frequency thereof.

11. The regulator of claim 10 wherein said device having a reactive impedance is a capacitor.

12. The regulator of claim 11 wherein said capacitor integrates said output portion received thereby to provide monotonic signal of predetermined duration which is greater than the monotonic duration of the corresponding waveform of said output.

13. The regulator of claim 10 wherein said capacitor is connected so as to have a decreasing impedance with increasing frequency so as to increase said control signal in accordance with increases in the frequency of said output portion received thereby.

14. The regulator of claim 13 further including a resistor connected in parallel with said capacitor.

15. The regulator of claim 12 further including a second capacitor connected so as to have a decreasing impedance with increasing frequency so as to increase in said control signal in accordance with increases in the frequency of said output portion received thereby.

16. The regulator of claim 15 wherein said second capacitor receives said monotonic signal from said first capacitor.

17. The regulator of claim 10 wherein said device having a reactive impedance is connected to said output winding through a resistor and wherein said resistor establishes the response of said control means to the amplitude of said output.

18. The regulator of claim 17 wherein said control circuit includes a resistive voltage divider and said resistor is a component of said resistive voltage divider.

19. In combination, a permanent magnet generator having an output winding for providing an output having a waveform of cyclically varying amplitude and definable amplitude peak, a load connected to said output winding for receiving at least a portion of said output, and regulating means comprising switch means being operable for establishing a relatively low impedance path across said output winding responsive to a control signal, and control means for providing said control signal having capacitor connected to receive at least a portion of said output for integrating said output portion received thereby to provide a monotonic signal having a definable amplitude peak occurring subsequent to said peak of said output waveform, said monotonic signal being utilized to provide said control signal.

20. The combination of claim 19 further including a second capacitor connected so as to have a decreasing impedance with increasing frequency so as to increase said control signal in accordance with increases in the frequency of said output portion received thereby.

21. The combination of claim 20 wherein said second capacitor receives said monotonic signal from said first capacitor.

22. In combination, a permanent magnet generator having an output winding for providing an output having a cyclic waveform of varying amplitude with said waveform being monotonic for a determinable portion of the output cycle of said generator, a load connected to said output winding for receiving at least a portion of said output, and regulating means connected to said output .winding, said regulating means comprising switch means being operable for establishing a relatively low impedance path across said output winding responsive to a control signal, and control means receiving at least a portion of said output for modifying said received portion to provide said control signal, said control means including means modifying the waveform of said received portion to provide said control signal with a portion which is monotonic for a substantially greater portion of said output cycle than said monotonic portion of said output waveform.

23. The combination of claim 22 wherein said modifyingmeans includes a device having a reactive impedance for modifying said waveform of said received portion to provide said monotonic portion of said control signal.

24. The combination of claim 23 wherein said device having a reactive impedance is a capacitor.

25. The combination of claim 22 wherein said load is a lamp for emitting light.

26. For a permanent magnet generator having an output winding for providing an output to a load, said output having a cyclic waveform of varying amplitude with said waveform having a definable amplitude peak occurring at a determinable time in the output cycle of said generator, a regulator adapted for connection to said output winding comprising: switch means being operable for establishing a relatively low impedance path across said output winding responsive to a control signal, and control means receiving at least a portion of said output for providing said control signal, said control means including means for modifying the waveform of said received portion so that said control signal has an amplitude peak which substantially lags said amplitude peak of said output waveform.

27. The regulator of claim 26 wherein said modifying means includes a device having a reactive impedance for modifying said waveform of said received portion to provide said portion of said control signal having said amplitude peak.

28. The regulator of claim 27 wherein said device having a reactive impedance is a capacitor.

29. For a permanent magnet generator having an output windng for providing an output to a load, said output having a cyclic waveform of varying frequency amplitude, and varying in amplitude with variations in frequency and without variations in frequency, a regulator adapted for connection to said output winding comprising: switch means being operable for establishing a relatively low impedance path across said output winding responsive to a control signal, and control means receiving at least a portion of said output waveform including a circuit having a resistor selected in accordance with variations of the amplitude'of said waveform without variations in frequency and a capacitor selected in accordance with variations in the amplitude of said waveform with variations in frequency to provide said control signal to cause selective operation of said switch means to limit variations in the power level of said output received by said load.

30. The regulator of claim 29 wherein said switch means includes a control terminal and said capacitor is connected to said control terminal to provide said control signal to said control terminal to cause said selective operation of said switch, said capacitor providing a decrease in the impedance of the signal path for said control signal to said control terminal with increasing frequency so that said switching means provides said low impedance path across said output windings at earlier times in the output cycle of said generator for higher frequencies.

31. The regulator of claim 30 wherein said generator is an alternator providing a voltage waveform of alternating polarityv 32. In combination, a permanent magnet generator having an output winding for providing an output having a waveform of varying amplitude, a load connected to said output winding for receiving at least a portion of said output, and regulating means connected to said output winding, said regulating means comprising switch means having a control terminal being operable for establishing a relatively low impedance path across said output winding responsive to a control signal at said control terminal, and control means receiving at least a portion of said output for providing said control signal to cause selective operation of said switch means to limit variations in the power level of said portion of said output received by said load, said control means comprising a resistor connected to receive said output portion received by said control circuit to provide a first signal having a reduced amplitude determined in accordance with the output power characteristics of said generator, a first capacitor receiving said first signal and being connected to provide a second signal representing an integral function of said first signal so that said second signal has a monotonic portion which is extended relative to a corresponding monotonic portion of said output waveform, and a second capacitor connecting said first capacitor with said control circuit for providing a decreasing impedance path to said control terminal for said second signal with increasing frequency determined in accordance with the output power characteritstics of said generator to thereby modify said second signal with frequency to provide said control signal.

33. The combination of claim 32 wherein said generator is an alternator providing a voltage waveform of alternating polarity and wherein said control means further includes a diode connecting said resistor to said output winding so that said control circuit output portion comprises a half wave signal.

34. The combination of claim 33 wherein said first resistor is associated with a circuit providing a time constant which is longer than the period of said output waveform for a portion of the operating frequency range of said generator.

35. The combination of claim 32 further including a second resistor connected in series with said first resistor to form a resistive voltage divider, said resistive voltage divider being connected across said output winding and said first capacitor being connected intermediate said first and second resistors.

36. The combination of claim 32 wherein said first resistor is associated with a circuit providing a time constant which is longer than the period of said output waveform for a portion of the operating frequency range of said generator.

37. For a permanent magnet generator having an output winding for providing an output to a load having a waveform of varying amplitude, regulating means adapted for connection to said output winding comprising switch means having a control terminal being operable for establishing a relatively low impedance path across said output winding responsive to a control sig nal at said control terminal, and control means receiving at least a portion of said output for providing said control signal to cause selective operation of said switch means to limit variations in the power level of said output received by said load, said control means comprising a resistor connected to receive said output portion received by said control circuit to provide a first signal having a reduced amplitude determined in accordance with the output power characteristics of said generator, a first capacitor receiving said first signal and being connected to provide a second signal representing an integral function of said first signal so that said second signal has a monotonic portion which is extended relative to a corresponding monotonic portion of said output waveform, and a second capacitor connecting said first capacitor with said control circuit for providing a decreasing impedance path to said control terminal for said second signal with increasing frequency determined in accordance with the output power characteristics of said generator to thereby modify said second signal with frequency to provide said control signal.

38. The regulating means of claim 37 wherein said generator is an alternator providing a voltage waveform of alternating polarity and wherein said control means further includes a diode connecting said resistor to said output winding so that said control circuit output portion comprises a halfwave signal.

39. The regulating means of claim 38 wherein said first resistor is associated with a circuit providing a time constant which is longer than the period of said output waveform for a portion of the operating frequency range of said generator.

40. The regulating means of claim 37 further including a second resistor connected in series with said first resistor to form a resistive voltage divider, said resistive voltage divider being connected across said output winding and said first capacitor being connected intermediate said first and second resistors.

41. The regulating means of claim 37 wherein said first resistor is associated with a circuit providing a time constant which is longer than the period of said output waveform for a portion of the operating frequency range of said generator.

42. In combination, a permanent magnet generator having an output winding for providing an alternating current output having a waveform of varying amplitude, a load connected to said output winding for receiving at least a portion of said output, and regulating means connected to said output winding for reducing the power output of said generator responsive to a control signal including control means receiving at least a portion of said alternating current output responsive to said output for providing said control signal in accordance with the frequency of said output to limit variations in the power level of said portion of said output received by said load.

43. The combination of claim 42 wherein said control means is further responsive to the amplitude of said output waveform so as to provide said control signal in accordance thereto.

44. In combination, a permanent magnet generator having an output winding for providing an alternating current output having a waveform of varying amplitude, a load connected to said output winding for receiving at least a portion of said output, and regulating means connected to said output winding, said regulating means comprising switch means being operable for establishing a relatively low impedance path across said output winding responsive to a control signal, and control means receiving at least a portion of said altemating current output responsive to the frequency of said output for providing said control signal to cause selective operation of said switch means to limit variations in the power level of said portion of said output received by said load, said regulating circuit wholly consisting of solid state components.

45. The combination of claim 44 wherein said control means is further responsive to the amplitude of said output waveform so as to provide said control signal in accordance thereto.

46. For a permanent magnet generator having an out put winding for providing an output having a waveform of varying polarity and amplitude to a load, and being adapted for connection for providing at least a portion of said output to said load, a regulator adapted for connection to said output winding comprising first switch means being operable for establishing a relatively low impedance path across said output winding responsive to a first control signal when said output is of a first polarity, second switch means being operable for establishing a relatively low impedance path across said output winding responsive to a second control signal when said output is of a second polarity, and control means receiving at least a portion of said varying polarity output waveform and responsive to the frequency of said output for providing said first control signal to cause selective operation of said first switch means and for providing a second control signal to cause selective operation of said second switch means to limit variations in the power level of said portion of said output received by said load.

47. The regulator according to claim 46 wherein said control means is further responsive to the amplitude of said output for limiting variations in the power level of said portion of said output received by said load.

48. For a permanent magnet generator having an output winding for providing an alternating current output having a waveform of varying amplitude and being adapted for connection to a load for providing at elast a portion of said output to said load, a regulator adapted for connection to said output winding comprising switch means being oprable for establishing a relatively low impedance path across said output winding responsive to each of a first control signal and a second control signal, first control means receiving at least a portion of said alternating current output and responsive to the frequency of said output for providing said first control signal to cause selective operation of said switch means to limit variations in the power level of said portion of said output received by said load, and second control means responsive to the amplitude of said output for providing said second control signal tocause selective operation of said switch means to limit the amplitude of said portion of said output received by said load.

49. The regulator according to claim 48 wherein said amplitude is the amplutude of the potential across said output winding.

50. The regulator according to claim 49 wherein said second control means is a zener diode connected to said output winding which is adapted to break down at a predetermined high potential across said output winding to cause said switch means to establish said relatively low impedance path across said output winding for absorbing said high potential.

51. The regulator according to claim 50 wherein said switch means is an SCR having a gate and said zener diode is connected to the gate of said SCR for firing said SCR upon breakdown of said zener diode.

52. For a permanent magnet generator having an output winding for providing an output having a waveform of varying polarity and amplitude and being adapted for connection to a load for providing at least a portion of said output to said load, a regulator adapted for connection to said output winding comprising first switch means being operable for establishing a relatively low impedance path across said output winding responsive to each of a first control signal and a second control signal when said output is of a first polarity, second switch means being operable for establishing a relatively low impedance path across said output winding responsive to each of a third control signal and a fourth control signal when said output is of a second polarity, first control means responsive to the frequency of said output for providing said first and third control signals to cause selective operation of said first and second switch means to limit variations in the power level of said portion of said output received by said load, and second control means responsive to the amplitude of said output for providing said second and fourth control signals to cause selective operation of said switch means to limit the amplitude of said portion of said output received by said load.

53. The regulator according to claim 52 wherein said amplitude is the amplitude of the potential across said output winding.

54. The regulator according to claim 53 wherein said output winding has a pair of output terminals, and said second control means includes a pair of zener diodes with one of said zener diodes being connected to one output tenninal of said output winding and the other of said zener diodes being connected to the other output terminal of said output winding, said zener diodes being adapted to break down at a predetermined high potential across said output winding to cause said first and second switch means to establish said relatively low impedance path across said output winding for absorbing said high potential.

55. The regulator according to claim 54 wherein each of said first and second switch means is an SCR having a gate, and wherein each of said zener diodes is connected to the gate of a respective one SCR for firing said respective one said SCR upon breakdown of said respective one of said zener diodes. 

1. For a permanent magnet generator having an output winding for providing an alternating current output having a waveform of varying amplitude and being adapted for connection to a load for providing at least a portion of said output to said load, a regulator adapted for connection to said output winding comprising switch means being operable for establishing a relatively low impedance path across said output winding responsive to a control signal, and control means receiving at least a portion of said alternating current output and responsive to the frequency of said output for providing said control signal to cause selective operation of said switch means to limit variations in the power level of said portion of said output received by said load.
 2. The regulator of claim 1 wherein said control means includes a device having a reactive impedance receiving at least a portion of said output portion received by said control means for modifying said output portion received thereby in accordance with the frequency thereof.
 3. The regulator of claim 2 wherein said device having a reactive impedance is a capacitor.
 4. The regulator of claim 3 wherein said capacitor integrates said output portion received thereby to provide monotonic signal of predetermined duration which is greater than the monotonic duration of the corresponding waveform of said output.
 5. The regulator of claim 2 wherein said capacitor is connected so as to have a decreasing impedance with increasing frequency so as to increase said control signal in accordance with increases in the frequency of said output portion received thereby.
 6. The regulator of claim 5 further including a resistor connected in parallel with said capacitor.
 7. The regulator of claim 4 further including a second capacitor connected so as to have a decreasing impedance with increasing frequency so as to increase said control signal in accordance with increases in the frequency of said output portion received thereby.
 8. The regulator of claim 7 wherein said second capacitor receives said monotonic signal from said first capacitor.
 9. For a permanent magnet generator having an output winding for providing an alternating current output having a waveform of varying amplitude and being adapted for connection to a load for providing at least a portion of said output to said load, a regulator adapted for connection to said output winding, said regulating means comprising switch means being operable for establishing a relatively low impedance path across said output winding responsive to a control signal, and control means receiving at least a portion of said alternating current output and responsive to the frequency and amplitude of said output for providing said control signal to cause selective operation of said switch means to limit variations in the power level of saId portion of said output received by said load.
 10. The regulator of claim 9 wherein said control means includes a device having a reactive impedance receiving at least a portion of said output received by said control means for modifying said output portion received thereby in accordance with the frequency thereof.
 11. The regulator of claim 10 wherein said device having a reactive impedance is a capacitor.
 12. The regulator of claim 11 wherein said capacitor integrates said output portion received thereby to provide monotonic signal of predetermined duration which is greater than the monotonic duration of the corresponding waveform of said output.
 13. The regulator of claim 10 wherein said capacitor is connected so as to have a decreasing impedance with increasing frequency so as to increase said control signal in accordance with increases in the frequency of said output portion received thereby.
 14. The regulator of claim 13 further including a resistor connected in parallel with said capacitor.
 15. The regulator of claim 12 further including a second capacitor connected so as to have a decreasing impedance with increasing frequency so as to increase in said control signal in accordance with increases in the frequency of said output portion received thereby.
 16. The regulator of claim 15 wherein said second capacitor receives said monotonic signal from said first capacitor.
 17. The regulator of claim 10 wherein said device having a reactive impedance is connected to said output winding through a resistor and wherein said resistor establishes the response of said control means to the amplitude of said output.
 18. The regulator of claim 17 wherein said control circuit includes a resistive voltage divider and said resistor is a component of said resistive voltage divider.
 19. In combination, a permanent magnet generator having an output winding for providing an output having a waveform of cyclically varying amplitude and a definable amplitude peak, a load connected to said output winding for receiving at least a portion of said output, and regulating means comprising switch means being operable for establishing a relatively low impedance path across said output winding responsive to a control signal, and control means for providing said control signal having capacitor connected to receive at least a portion of said output for integrating said output portion received thereby to provide a monotonic signal having a definable amplitude peak occurring subsequent to said peak of said output waveform, said monotonic signal being utilized to provide said control signal.
 20. The combination of claim 19 further including a second capacitor connected so as to have a decreasing impedance with increasing frequency so as to increase said control signal in accordance with increases in the frequency of said output portion received thereby.
 21. The combination of claim 20 wherein said second capacitor receives said monotonic signal from said first capacitor.
 22. In combination, a permanent magnet generator having an output winding for providing an output having a cyclic waveform of varying amplitude with said waveform being monotonic for a determinable portion of the output cycle of said generator, a load connected to said output winding for receiving at least a portion of said output, and regulating means connected to said output winding, said regulating means comprising switch means being operable for establishing a relatively low impedance path across said output winding responsive to a control signal, and control means receiving at least a portion of said output for modifying said received portion to provide said control signal, said control means including means modifying the waveform of said received portion to provide said control signal with a portion which is monotonic for a substantially greater portion of said output cycle than said monotonic portion of said output waveform.
 23. The combination of claim 22 wherein said modifying meAns includes a device having a reactive impedance for modifying said waveform of said received portion to provide said monotonic portion of said control signal.
 24. The combination of claim 23 wherein said device having a reactive impedance is a capacitor.
 25. The combination of claim 22 wherein said load is a lamp for emitting light.
 26. For a permanent magnet generator having an output winding for providing an output to a load, said output having a cyclic waveform of varying amplitude with said waveform having a definable amplitude peak occurring at a determinable time in the output cycle of said generator, a regulator adapted for connection to said output winding comprising: switch means being operable for establishing a relatively low impedance path across said output winding responsive to a control signal, and control means receiving at least a portion of said output for providing said control signal, said control means including means for modifying the waveform of said received portion so that said control signal has an amplitude peak which substantially lags said amplitude peak of said output waveform.
 27. The regulator of claim 26 wherein said modifying means includes a device having a reactive impedance for modifying said waveform of said received portion to provide said portion of said control signal having said amplitude peak.
 28. The regulator of claim 27 wherein said device having a reactive impedance is a capacitor.
 29. For a permanent magnet generator having an output winding for providing an output to a load, said output having a cyclic waveform of varying frequency amplitude, and varying in amplitude with variations in frequency and without variations in frequency, a regulator adapted for connection to said output winding comprising: switch means being operable for establishing a relatively low impedance path across said output winding responsive to a control signal, and control means receiving at least a portion of said output waveform including a circuit having a resistor selected in accordance with variations of the amplitude of said waveform without variations in frequency and a capacitor selected in accordance with variations in the amplitude of said waveform with variations in frequency to provide said control signal to cause selective operation of said switch means to limit variations in the power level of said output received by said load.
 30. The regulator of claim 29 wherein said switch means includes a control terminal and said capacitor is connected to said control terminal to provide said control signal to said control terminal to cause said selective operation of said switch, said capacitor providing a decrease in the impedance of the signal path for said control signal to said control terminal with increasing frequency so that said switching means provides said low impedance path across said output windings at earlier times in the output cycle of said generator for higher frequencies.
 31. The regulator of claim 30 wherein said generator is an alternator providing a voltage waveform of alternating polarity.
 32. In combination, a permanent magnet generator having an output winding for providing an output having a waveform of varying amplitude, a load connected to said output winding for receiving at least a portion of said output, and regulating means connected to said output winding, said regulating means comprising switch means having a control terminal being operable for establishing a relatively low impedance path across said output winding responsive to a control signal at said control terminal, and control means receiving at least a portion of said output for providing said control signal to cause selective operation of said switch means to limit variations in the power level of said portion of said output received by said load, said control means comprising a resistor connected to receive said output portion received by said control circuit to provide a first signal having a reduced amplitude determined in accorDance with the output power characteristics of said generator, a first capacitor receiving said first signal and being connected to provide a second signal representing an integral function of said first signal so that said second signal has a monotonic portion which is extended relative to a corresponding monotonic portion of said output waveform, and a second capacitor connecting said first capacitor with said control circuit for providing a decreasing impedance path to said control terminal for said second signal with increasing frequency determined in accordance with the output power characteristics of said generator to thereby modify said second signal with frequency to provide said control signal.
 33. The combination of claim 32 wherein said generator is an alternator providing a voltage waveform of alternating polarity and wherein said control means further includes a diode connecting said resistor to said output winding so that said control circuit output portion comprises a half wave signal.
 34. The combination of claim 33 wherein said first resistor is associated with a circuit providing a time constant which is longer than the period of said output waveform for a portion of the operating frequency range of said generator.
 35. The combination of claim 32 further including a second resistor connected in series with said first resistor to form a resistive voltage divider, said resistive voltage divider being connected across said output winding and said first capacitor being connected intermediate said first and second resistors.
 36. The combination of claim 32 wherein said first resistor is associated with a circuit providing a time constant which is longer than the period of said output waveform for a portion of the operating frequency range of said generator.
 37. For a permanent magnet generator having an output winding for providing an output to a load having a waveform of varying amplitude, regulating means adapted for connection to said output winding comprising switch means having a control terminal being operable for establishing a relatively low impedance path across said output winding responsive to a control signal at said control terminal, and control means receiving at least a portion of said output for providing said control signal to cause selective operation of said switch means to limit variations in the power level of said output received by said load, said control means comprising a resistor connected to receive said output portion received by said control circuit to provide a first signal having a reduced amplitude determined in accordance with the output power characteristics of said generator, a first capacitor receiving said first signal and being connected to provide a second signal representing an integral function of said first signal so that said second signal has a monotonic portion which is extended relative to a corresponding monotonic portion of said output waveform, and a second capacitor connecting said first capacitor with said control circuit for providing a decreasing impedance path to said control terminal for said second signal with increasing frequency determined in accordance with the output power characteristics of said generator to thereby modify said second signal with frequency to provide said control signal.
 38. The regulating means of claim 37 wherein said generator is an alternator providing a voltage waveform of alternating polarity and wherein said control means further includes a diode connecting said resistor to said output winding so that said control circuit output portion comprises a halfwave signal.
 39. The regulating means of claim 38 wherein said first resistor is associated with a circuit providing a time constant which is longer than the period of said output waveform for a portion of the operating frequency range of said generator.
 40. The regulating means of claim 37 further including a second resistor connected in series with said first resistor to form a resistive voltage divider, Said resistive voltage divider being connected across said output winding and said first capacitor being connected intermediate said first and second resistors.
 41. The regulating means of claim 37 wherein said first resistor is associated with a circuit providing a time constant which is longer than the period of said output waveform for a portion of the operating frequency range of said generator.
 42. In combination, a permanent magnet generator having an output winding for providing an alternating current output having a waveform of varying amplitude, a load connected to said output winding for receiving at least a portion of said output, and regulating means connected to said output winding for reducing the power output of said generator responsive to a control signal including control means receiving at least a portion of said alternating current output responsive to said output for providing said control signal in accordance with the frequency of said output to limit variations in the power level of said portion of said output received by said load.
 43. The combination of claim 42 wherein said control means is further responsive to the amplitude of said output waveform so as to provide said control signal in accordance thereto.
 44. In combination, a permanent magnet generator having an output winding for providing an alternating current output having a waveform of varying amplitude, a load connected to said output winding for receiving at least a portion of said output, and regulating means connected to said output winding, said regulating means comprising switch means being operable for establishing a relatively low impedance path across said output winding responsive to a control signal, and control means receiving at least a portion of said alternating current output responsive to the frequency of said output for providing said control signal to cause selective operation of said switch means to limit variations in the power level of said portion of said output received by said load, said regulating circuit wholly consisting of solid state components.
 45. The combination of claim 44 wherein said control means is further responsive to the amplitude of said output waveform so as to provide said control signal in accordance thereto.
 46. For a permanent magnet generator having an output winding for providing an output having a waveform of varying polarity and amplitude to a load, and being adapted for connection for providing at least a portion of said output to said load, a regulator adapted for connection to said output winding comprising first switch means being operable for establishing a relatively low impedance path across said output winding responsive to a first control signal when said output is of a first polarity, second switch means being operable for establishing a relatively low impedance path across said output winding responsive to a second control signal when said output is of a second polarity, and control means receiving at least a portion of said varying polarity output waveform and responsive to the frequency of said output for providing said first control signal to cause selective operation of said first switch means and for providing a second control signal to cause selective operation of said second switch means to limit variations in the power level of said portion of said output received by said load.
 47. The regulator according to claim 46 wherein said control means is further responsive to the amplitude of said output for limiting variations in the power level of said portion of said output received by said load.
 48. For a permanent magnet generator having an output winding for providing an alternating current output having a waveform of varying amplitude and being adapted for connection to a load for providing at least a portion of said output to said load, a regulator adapted for connection to said output winding comprising switch means being operable for establishing a relatively low impedance path across said output winding responsive to each of a first control signal and a second control signal, first control means receiving at least a portion of said alternating current output and responsive to the frequency of said output for providing said first control signal to cause selective operation of said switch means to limit variations in the power level of said portion of said output received by said load, and second control means responsive to the amplitude of said output for providing said second control signal to cause selective operation of said switch means to limit the amplitude of said portion of said output received by said load.
 49. The regulator according to claim 48 wherein said amplitude is the amplitude of the potential across said output winding.
 50. The regulator according to claim 49 wherein said second control means is a zener diode connected to said output winding which is adapted to break down at a predetermined high potential across said output winding to cause said switch means to establish said relatively low impedance path across said output winding for absorbing said high potential.
 51. The regulator according to claim 50 wherein said switch means is an SCR having a gate and said zener diode is connected to the gate of said SCR for firing said SCR upon breakdown of said zener diode.
 52. For a permanent magnet generator having an output winding for providing an output having a waveform of varying polarity and amplitude and being adapted for connection to a load for providing at least a portion of said output to said load, a regulator adapted for connection to said output winding comprising first switch means being operable for establishing a relatively low impedance path across said output winding responsive to each of a first control signal and a second control signal when said output is of a first polarity, second switch means being operable for establishing a relatively low impedance path across said output winding responsive to each of a third control signal and a fourth control signal when said output is of a second polarity, first control means responsive to the frequency of said output for providing said first and third control signals to cause selective operation of said first and second switch means to limit variations in the power level of said portion of said output received by said load, and second control means responsive to the amplitude of said output for providing said second and fourth control signals to cause selective operation of said switch means to limit the amplitude of said portion of said output received by said load.
 53. The regulator according to claim 52 wherein said amplitude is the amplitude of the potential across said output winding.
 54. The regulator according to claim 53 wherein said output winding has a pair of output terminals, and said second control means includes a pair of zener diodes with one of said zener diodes being connected to one output terminal of said output winding and the other of said zener diodes being connected to the other output terminal of said output winding, said zener diodes being adapted to break down at a predetermined high potential across said output winding to cause said first and second switch means to establish said relatively low impedance path across said output winding for absorbing said high potential.
 55. The regulator according to claim 54 wherein each of said first and second switch means is an SCR having a gate, and wherein each of said zener diodes is connected to the gate of a respective one SCR for firing said respective one said SCR upon breakdown of said respective one of said zener diodes. 